U.S. patent application number 15/745909 was filed with the patent office on 2018-07-26 for carbide producing method and carbide producing device.
The applicant listed for this patent is MITSUBISHI HEAVY INDUSTRIES ENVIRONMENTAL & CHEMICAL ENGINEERING CO., LTD.. Invention is credited to Yuuki ENDOU, Tomoki ICHINOSE, Keiichi ISHIKAWA.
Application Number | 20180208851 15/745909 |
Document ID | / |
Family ID | 57884735 |
Filed Date | 2018-07-26 |
United States Patent
Application |
20180208851 |
Kind Code |
A1 |
ENDOU; Yuuki ; et
al. |
July 26, 2018 |
CARBIDE PRODUCING METHOD AND CARBIDE PRODUCING DEVICE
Abstract
A carbide producing method for carbonizing a woody biomass to
produce a carbide includes a pyrolysis process in which the woody
biomass is pyrolyzed and carbonized, an LHV calculating process in
which an LHV of the carbide which is a carbonized woody biomass is
calculated, and a supplied heat amount control process in which an
amount of heat supplied per unit time to the woody biomass in the
pyrolysis process on the basis of the calculated LHV is
controlled.
Inventors: |
ENDOU; Yuuki; (Yokohama-shi,
JP) ; ICHINOSE; Tomoki; (Yokohama-shi, Kanagawa,
JP) ; ISHIKAWA; Keiichi; (Yokohama-shi, Kanagawa,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MITSUBISHI HEAVY INDUSTRIES ENVIRONMENTAL & CHEMICAL
ENGINEERING CO., LTD. |
Yokohama-shi, Kanagawa |
|
JP |
|
|
Family ID: |
57884735 |
Appl. No.: |
15/745909 |
Filed: |
July 30, 2015 |
PCT Filed: |
July 30, 2015 |
PCT NO: |
PCT/JP2015/071643 |
371 Date: |
January 18, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10B 1/10 20130101; C10B
53/02 20130101; C10L 2290/58 20130101; C10L 2290/60 20130101; C10B
21/10 20130101; C10L 2290/02 20130101; Y02E 50/30 20130101; Y02E
50/14 20130101; Y02E 50/10 20130101; C10B 7/10 20130101; C10B 47/30
20130101; C10L 5/447 20130101; C10L 2290/06 20130101; C01B 32/90
20170801; C10L 9/08 20130101 |
International
Class: |
C10B 21/10 20060101
C10B021/10; C10B 53/02 20060101 C10B053/02; C10B 47/30 20060101
C10B047/30; C10B 7/10 20060101 C10B007/10; C01B 32/90 20060101
C01B032/90; C10L 5/44 20060101 C10L005/44 |
Claims
1. A carbide producing method comprising: a pyrolysis process in
which a woody biomass is pyrolyzed and carbonized; an LHV
calculating process in which an LHV of a carbide which is a
carbonized woody biomass is calculated; and a supplied heat amount
control process in which an amount of heat supplied per unit time
to the woody biomass in the pyrolysis process is controlled on the
basis of the calculated LHV.
2. The carbide producing method according to claim 1, wherein, in
the LHV calculating process, the LHV is calculated on the basis of
a measurement value of a bulk density of the carbide.
3. The carbide producing method according to claim 1, wherein, in
the pyrolysis process, an amount of heat supplied per unit time to
the woody biomass is corrected on the basis of a moisture content
of the pyrolyzed woody biomass.
4. A carbide producing device comprising: a pyrolysis furnace in
which a woody biomass received from an inlet is moved to an outlet
and is pyrolyzed and carbonized; and a control device configured to
control an amount of heat supplied to the woody biomass in the
pyrolysis furnace, wherein the control device includes an LHV
calculating unit configured to calculate an LHV of a carbide which
is a carbonized woody biomass, and a supplied heat amount control
unit configured to control an amount of heat supplied per unit time
to the woody biomass on the basis of the calculated LHV.
5. The carbide producing device according to claim 4, comprising a
bulk density measuring device configured to measure a bulk density
of the carbide discharged from the pyrolysis furnace, wherein the
LHV calculating unit calculates the LHV on the basis of the bulk
density of the carbide measured by the bulk density measuring
device.
6. The carbide producing device according to claim 4, comprising a
moisture content measuring device configured to measure a moisture
content of the woody biomass put into the pyrolysis furnace,
wherein the control device corrects an amount of heat supplied per
unit time to the woody biomass on the basis of a moisture content
of the woody biomass.
7. The carbide producing device according to claim 4, wherein the
pyrolysis furnace includes an outer cylinder; an inner cylinder
that rotates relative to the outer cylinder; a heater configured to
supply a heating gas between the outer cylinder and the inner
cylinder; a drive device configured to rotate the inner cylinder;
and a heating gas amount adjusting device configured to adjust a
flow rate of a heating gas supplied from the heater, wherein the
control device includes a rotational speed adjusting unit
configured to control a rotational speed of the inner cylinder
using the drive device; and a heating gas amount adjusting unit
configured to control a flow rate of the heating gas using the
heating gas amount adjusting device, and wherein the supplied heat
amount control unit controls an amount of heat supplied per unit
time to the woody biomass by controlling at least one of the
rotational speed adjusting unit and the heating gas amount
adjusting unit.
Description
TECHNICAL FIELD
[0001] The present invention relates to a carbide producing method
and a carbide producing device through which a carbide is produced
by pyrolyzing woody biomass.
BACKGROUND ART
[0002] Attempts to increase a calorific value by performing a
carbonizing treatment on woody biomass have been made for the
purpose of utilizing the energy of woody biomass more efficiently.
As the carbonizing treatment for woody biomass, for example, a
method in which a pyrolysis furnace such as an external heat type
pyrolysis gasification furnace is used, woody biomass is indirectly
heated at a high temperature of 300.degree. C. to 700.degree. C.
under a low oxygen atmosphere, and thus a carbide with an increased
heat amount is produced is known.
[0003] As carbide producing methods, high temperature carbonization
in which woody biomass is indirectly heated at a high temperature
of 500.degree. C. to 700.degree. C. and half carbonization
(torrefaction) in which woody biomass is indirectly heated at about
300.degree. C. are known. In the high temperature carbonization, a
sufficient treatment time is ensured at a predetermined temperature
and thus it is possible to produce a carbide with a high
gasification rate and a reduced self-heating property. In the half
carbonization, by performing control within a very narrow
temperature range, it is possible to produce a carbide in which
both crushability and a residual calorific amount are compatible
(for example, refer to Patent Literature 1).
CITATION LIST
Patent Literature
[Patent Literature 1]
[0004] Japanese Unexamined Patent Application, First Publication
No. 2012-219176
SUMMARY OF INVENTION
Technical Problem
[0005] Incidentally, when co-combustion power generation in which a
carbide is mixed with coal and combusted, for example, and power is
generated in a coal fired power plant, in order to increase a
content of the carbide with respect to the coal, crushability in a
pulverizer such as a roller mill is important. That is, when a
carbide with poor crushability is mixed with coal and is
pulverized, a pulverizing power of the roller mill should exceed an
acceptable value of the pulverizing power.
[0006] Therefore, it is necessary to consider the crushability of
the carbide when a carbide appropriate for co-combustion power
generation is produced. In addition, when a moisture content of a
woody biomass which is a raw material of a carbide varies, since
the crushability of the carbide varies, it is desirable to secure a
more stable quality.
[0007] An object of the present invention is to produce a carbide
having favorable crushability in a carbide producing method and a
carbide producing device through which a woody biomass is pyrolyzed
and carbonized.
Solution to Problem
[0008] According to a first aspect of the present invention, a
carbide producing method includes a pyrolysis process in which a
woody biomass is pyrolyzed and carbonized; an LHV calculating
process in which an LHV of a carbide which is a carbonized woody
biomass is calculated; and a supplied heat amount control process
in which an amount of heat supplied per unit time to the woody
biomass in the pyrolysis process is controlled on the basis of the
calculated LHV.
[0009] In such a configuration, when an amount of heat supplied per
unit time to the woody biomass is controlled on the basis of the
LHV of the carbide, it is possible to produce a carbide having
favorable crushability. That is, when an amount of heat supplied to
the woody biomass is adjusted using a correlation between the LHV
of the carbide and the crushability of the carbide so that the LHV
of the carbide has an appropriate value, it is possible to produce
a carbide with a stable quality.
[0010] In the LHV calculating process, the LHV may be calculated on
the basis of a measurement value of a bulk density of the
carbide.
[0011] In such a configuration, when the LHV of the carbide is
calculated using a correlation between the bulk density of the
carbide and the LHV of the carbide, it is possible to ascertain the
LHV of the carbide quickly. Since there is a high correlation
between the LHV of the carbide and the bulk density of the carbide,
it is possible to calculate the LHV of the carbide immediately in
contrast to a method of analyzing a carbide or the like.
[0012] In the pyrolysis process, an amount of heat supplied per
unit time to the woody biomass may be corrected on the basis of a
moisture content of the pyrolyzed woody biomass.
[0013] In such a configuration, if a moisture content of the woody
biomass deviates from an appropriate numerical value, the moisture
content of the woody biomass can be brought close to an appropriate
numerical value.
[0014] According to a second aspect of the present invention, there
is provided a carbide producing device, including a pyrolysis
furnace in which a woody biomass received from an inlet is moved to
an outlet and is pyrolyzed and carbonized; and a control device
configured to control an amount of heat supplied to the woody
biomass in the pyrolysis furnace, wherein the control device
includes an LHV calculating unit configured to calculate an LHV of
a carbide which is a carbonized woody biomass, and a supplied heat
amount control unit configured to control an amount of heat
supplied per unit time to the woody biomass on the basis of the
calculated LHV.
[0015] The carbide producing device may include a bulk density
measuring device configured to measure a bulk density of the
carbide discharged from the pyrolysis furnace. The LHV calculating
unit may calculate the LHV on the basis of the bulk density of the
carbide measured by the bulk density measuring device.
[0016] The carbide producing device may include a moisture content
measuring device configured to measure a moisture content of the
woody biomass put into the pyrolysis furnace. The control device
may correct an amount of heat supplied per unit time to the woody
biomass on the basis of a moisture content of the woody
biomass.
[0017] In the carbide producing device, the pyrolysis furnace may
include an outer cylinder; an inner cylinder that rotates relative
to the outer cylinder; a heater configured to supply a heating gas
between the outer cylinder and the inner cylinder; a drive device
configured to rotate the inner cylinder; and a heating gas amount
adjusting device configured to adjust a flow rate of a heating gas
supplied from the heater, the control device may include a
rotational speed adjusting unit configured to control a rotational
speed of the inner cylinder using the drive device; and a heating
gas amount adjusting unit configured to control a flow rate of the
heating gas using the heating gas amount adjusting device, and the
supplied heat amount control unit may control an amount of heat
supplied per unit time to the woody biomass by controlling at least
one of the rotational speed adjusting unit and the heating gas
amount adjusting unit.
Advantageous Effects of Invention
[0018] According to the present invention, it is possible to
produce a carbide having favorable crushability.
BRIEF DESCRIPTION OF DRAWINGS
[0019] FIG. 1 is a schematic configuration diagram showing an
example of a carbide producing device according to an embodiment of
the present invention.
[0020] FIG. 2 is a graph showing a correlation between an LHV of a
carbide and a pulverizing power of a pulverizer.
[0021] FIG. 3 is a graph showing a correlation between an LHV of a
carbide and a bulk density of a carbide.
DESCRIPTION OF EMBODIMENTS
[0022] A carbide producing device according to an embodiment of the
present invention will be described below in detail with reference
to the drawings. FIG. 1 is a schematic configuration diagram
showing an example of a carbide producing device according to the
present embodiment.
[0023] As shown in FIG. 1, the carbide producing device according
to the present embodiment includes a screw conveyor 2 through which
a woody biomass B serving as a raw material is conveyed, an
external heat type pyrolysis gasification furnace 3 in which the
woody biomass B put into from the screw conveyor 2 is pyrolyzed and
carbonized, a chute 4 from which a carbide C discharged from the
external heat type pyrolysis gasification furnace 3 is discharged,
a bulk density measuring device 5 configured to measure a bulk
density of the carbide C discharged from the chute 4, and a control
device 6 configured to control the external heat type pyrolysis
gasification furnace 3 as main components.
[0024] The woody biomass B is a biomass made of wood (biological
resources), and forest residues such as branches and leaves
generated when wood is cut and materials are prepared, and wood
pellets and wood chips generated from bark, sawdust, and the like
generated in sawmilling factories.
[0025] The external heat type pyrolysis gasification furnace 3 is
an indirect heating type pyrolysis furnace in which the woody
biomass B is indirectly heated to cause a pyrolysis or gasification
reaction.
[0026] The external heat type pyrolysis gasification furnace 3 is
an external heat type rotary kiln furnace that includes an outer
cylinder 8 (muffle) and an inner cylinder 9 (kiln shell) which
rotates relative to the outer cylinder 8 and into which the woody
biomass B is put.
[0027] In the carbide producing device according to the present
embodiment, an external heat type rotary kiln furnace is used as
the external heat type pyrolysis gasification furnace 3. However,
the present invention is not limited thereto as long as the furnace
is a type in which the woody biomass B may be indirectly heated.
For example, an external heat type screw conveyor may be used as
the external heat type pyrolysis gasification furnace 3.
[0028] The upstream side of the inner cylinder 9 can rotate about
an axis and is supported by a movable side support portion 10 that
is movable in an axial direction. The downstream side of the inner
cylinder 9 can rotate about the axis and is supported by a fixed
side support portion 13.
[0029] The screw conveyor 2 through which the woody biomass B is
put in the inner cylinder 9 is provided on the movable side support
portion 10 constituting an inlet of the inner cylinder 9 and the
chute 4 from which the carbide C is discharged is provided on the
fixed side support portion 13 constituting an outlet of the inner
cylinder 9.
[0030] The movable side support portion includes an annular frame
11 that can rotate and supports the inner cylinder 9. Both side
portions of the annular frame 11 can rotate and are supported on an
upper end of a support member 12 which is raised from an
installation surface 18 in a freely swinging manner.
[0031] A plurality of fins (or spirals, not shown) arranged to be
inclined in a circumferential direction are provided on the inner
wall of the inner cylinder 9. When the inner cylinder 9 is driven
and rotated at a predetermined rotational speed (for example, 1 to
5 rpm) by a drive device 14, it is possible to transfer the woody
biomass B received from the inlet side (upstream side) to the
outlet side (downstream side) while heating the woody biomass B.
Here, instead of providing the fins, the inner cylinder 9 can
rotate about an axis that is slightly inclined with respect to the
horizontal direction and is supported, and the woody biomass B can
be transferred to the outlet side by the inclination and the
rotation of the inner cylinder 9.
[0032] The drive device 14 includes a gear 15 provided on surface
of the inner cylinder 9, a drive motor 16, and a pinion gear 17
that is attached to a rotation shaft of the drive motor 16 and
fitted to the gear 15. The drive device 14 transmits driving of the
drive motor 16 to the gear 15 to rotate the gear 15 and thus
rotates the inner cylinder 9 around the axis.
[0033] The outer cylinder 8 is fixed to an installation portion
through a support member (not shown) while it allows rotation and
movement in the axial direction of the inner cylinder 9 and sealing
with the inner cylinder 9 is ensured.
[0034] The movable side support portion 10 and the fixed side
support portion 13 of the inner cylinder 9 form an air seal between
a rotating portion and a non-rotating portion. An expansion 27 for
absorbing displacement of the movable side support portion 10 in
the axial direction is provided in a portion connecting the movable
side support portion 10 and the screw conveyor 2.
[0035] A heating gas supply pipe 20 fed to heating gas from a
heating gas combustion furnace 19 functioning as a heater
configured to supply a heating gas is connected to one end of the
outer cylinder 8. A heating gas delivery pipe 21 is connected to
the other end of the outer cylinder 8. A heating gas amount
adjusting damper 22 and an induced draft fan 23 functioning as a
heating gas amount adjusting device 7 are provided in the heating
gas delivery pipe 21.
[0036] A plurality of inspection windows 24 are provided on an
upper portion of the outer cylinder 8 so as to be separated from
each other in the axial direction. In each of the inspection
windows 24, a non-contact thermometer 25 configured to measure a
kiln shell temperature (an iron shell temperature of the inner
cylinder 9) that faces an outer circumferential surface of the
inner cylinder 9 that rotates about the axis is provided. A
radiation thermometer can be used as the non-contact thermometer
25.
[0037] The control device 6 and the non-contact thermometer 25 are
connected communicatively, and the kiln shell temperature measured
by the non-contact thermometer 25 is input to the control device
6.
[0038] Since the kiln shell temperature is a temperature of a
portion that comes directly in contact with the woody biomass B in
the inner cylinder 9, a correlation with a pyrolysis temperature of
the woody biomass B and the kiln shell temperature is high, and
heating conditions are favorably reflected therein. Therefore, when
the temperature heating the woody biomass B is controlled on the
basis of the kiln shell temperature, it is possible to control the
heating temperature stably. In particular, the kiln shell
temperature varies depending on a moisture content of the woody
biomass B. When the moisture content of the woody biomass B
increases, since evaporation of moisture increases, the kiln shell
temperature decreases. The control device 6 of the present
embodiment uses the kiln shell temperature to measure a moisture
content of the woody biomass B. That is, the non-contact
thermometer 25 functions as a moisture content measuring
device.
[0039] A method of measuring a moisture content of the woody
biomass B is not limited to the above-described method. For
example, it may be directly measured using an electrical resistance
type sensor or a microwave type sensor.
[0040] The bulk density measuring device 5 includes a duct 28 into
which the carbide C discharged from the chute 4 is introduced and
two storage tanks 26 in which the carbide C introduced through the
duct 28 is stored. The duct 28 is divided into two ducts on the
downstream side. That is, the duct 28 includes an upstream side
duct 29 provided on the upstream side, a branching portion 30, and
a pair of downstream side ducts 31 provided downstream from the
branching portion 30. A switching damper 32 is provided at the
branching portion 30.
[0041] The carbide C introduced from the chute 4 into the upstream
side duct 29 is introduced into one of the downstream side ducts 31
by the switching damper 32. The pair of downstream side ducts 31
are disposed on a first storage tank 26a and a second storage tank
26b so that the carbide C is introduced. The switching damper 32 is
controlled by the control device 6.
[0042] A level meter 34 and a gravimeter 35 are provided at each of
the storage tanks 26. The level meter 34 is a sensor that can
detect the fact that a predetermined volume of the carbide C is
stored in the storage tank 26. When a predetermined volume of the
carbide C is stored in the storage tank 26, the level meter 34 can
transmit a signal to the control device 6. As the level meter 34,
for example, a sensor using infrared rays or a sensor using a
contact type switch can be used.
[0043] The gravimeter 35 is a device that can measure a weight of
the carbide C stored in the storage tank 26. The gravimeter 35 can
transmit the measured weight to the control device 6.
[0044] The control device 6 is a device that controls an amount of
heat supplied per unit time to the woody biomass B.
[0045] The control device 6 includes an LHV calculating unit 37
configured to calculate an LHV (lower heating value or net
calorific value) of the carbide C and a supplied heat amount
control unit 38 configured to control an amount of heat supplied
per unit time to the woody biomass B on the basis of the calculated
LHV.
[0046] In addition, the control device 6 includes a rotational
speed adjusting unit 39 configured to control a rotational speed of
the inner cylinder 9 using the drive device 14 and a heating gas
amount adjusting unit 40 configured to control a flow rate of a
heating gas using the heating gas amount adjusting device 7. The
rotational speed adjusting unit 39 and the heating gas amount
adjusting unit 40 are controlled by the supplied heat amount
control unit 38.
[0047] Here, as shown in FIG. 2, the inventors found that there is
a correlation between an LHV of a carbide and a pulverizing power
of a pulverizer such as a roller mill. FIG. 2 is a graph showing a
correlation between the LHV of the carbide and the pulverizing
power of the pulverizer. In FIG. 2, the horizontal axis represents
the LHV [MJ/kg] of the carbide and the vertical axis represents the
pulverizing power [kWh/t] of the pulverizer.
[0048] According to the graph (FIG. 2) obtained according to the
studies by the inventors, when the LHV of the carbide increases,
the pulverizing power of the pulverizer decreases (crushability of
a carbide is improved), and when the LHV of the carbide decreases,
the pulverizing power of the pulverizer increases.
[0049] Since the pulverizing power of the pulverizer then has an
allowable value L, it can be understood that the LHV of the carbide
needs to be X or more based on the graph.
[0050] The fact that the pulverizing power of the pulverizer is low
indicates that the crushability of the carbide is favorable and the
carbide has properties similar to those of coal. In addition, the
fact that the pulverizing power of the pulverizer is high indicates
that the crushability of the carbide is poor and the carbide has
properties similar to those of wood.
[0051] The LHV of the carbide can be increased by increasing an
amount of heat supplied per unit time to the woody biomass and can
be reduced by reducing an amount of heat supplied per unit time to
the woody biomass.
[0052] That is, in order to improve the crushability of the carbide
(increase the LHV of the carbide), it is necessary to increase an
amount of heat supplied per unit time to the woody biomass.
[0053] However, the LHV of the carbide is not necessarily high.
When an amount of heat supplied to the woody biomass is increased
too much in order to increase the LHV of the carbide, an excess
pyrolysis gas is generated due to pyrolysis and the yield
deteriorates. Therefore, the LHV of the carbide is a value
indicated by X in FIG. 2 or more and is preferably a value close to
X.
[0054] In addition, as shown in FIG. 3, the inventors found that
there is a correlation between an LHV of a carbide and a bulk
density of the carbide. FIG. 3 is a graph showing a correlation
between the LHV of the carbide and a bulk density of the carbide.
In FIG. 3, the horizontal axis represents the LHV [MJ/kg] of the
carbide and the vertical axis represents a bulk density
[g/cm.sup.3] of the carbide.
[0055] According to the graph (FIG. 3) obtained from the studies by
the inventors, when the bulk density decreases, the LHV of the
carbide increases, and when the bulk density increases, the LHV
decreases.
[0056] The control device 6 of the present embodiment can refer to
a table T (refer to FIG. 1) in which the correlation between the
bulk density and the LHV of the carbide shown in FIG. 3 is stored.
That is, the control device 6 can calculate the LHV of the carbide
on the basis of the bulk density of the carbide.
[0057] Next, a carbide producing method using the carbide producing
device according to the present embodiment will be described.
[0058] The carbide producing method of the present embodiment
includes a pyrolysis process in which a woody biomass B is
pyrolyzed and carbonized, an LHV calculating process in which an
LHV of a carbide C which is the carbonized woody biomass B is
calculated, and a supplied heat amount control process in which an
amount of heat supplied per unit time to the woody biomass B in the
pyrolysis process is controlled on the basis of the calculated
LHV.
[0059] A dryer (not shown) is disposed on the upstream side of the
external heat type pyrolysis gasification furnace 3, and the woody
biomass B which is dried by the dryer and includes moisture that is
adjusted to a predetermined amount is introduced into the inner
cylinder 9 of the external heat type pyrolysis gasification furnace
3 by the screw conveyor 2.
[0060] A heating gas from the heating gas combustion furnace 19 is
supplied into the outer cylinder 8 of the external heat type
pyrolysis gasification furnace 3 due to an induction action of the
induced draft fan 23, and the inner cylinder 9 positioned inside
the outer cylinder 8 is heated from the outer circumferential
surface due to the heating gas.
[0061] In the pyrolysis process, the woody biomass B introduced
into the inner cylinder 9 is indirectly heated and carbonized at a
high temperature of 300.degree. C. to 700.degree. C. under
conditions in which oxygen is almost excluded.
[0062] Specifically, the woody biomass B is transferred toward the
outlet side and heated as the inner cylinder 9 rotates.
Accordingly, first, moisture remaining in the woody biomass B is
evaporated. Pyrolysis of organic components occurs when moisture is
completely evaporated. As the pyrolysis proceeds, the woody biomass
B is carbonized while a pyrolysis gas G is generated and is
discharged from the chute 4 as the generated carbide C (solid fuel)
with a predetermined degree of carbonization.
[0063] On the other hand, the pyrolysis gas G generated due to the
pyrolysis is introduced from the chute 4 into the heating gas
combustion furnace 19 and is combusted together with an auxiliary
fuel and combustion air whose heat is exchanged in the heating gas
delivery pipe 21, and some of the combustion gas is refluxed to the
heating gas combustion furnace 19 and combusted together with an
auxiliary fuel in the heating gas combustion furnace 19, and is
used for heating in the external heat type pyrolysis gasification
furnace 3.
[0064] In the pyrolysis process, an amount of heat supplied per
unit time to the woody biomass B is adjusted by the heating gas
amount adjusting unit 40 and the rotational speed adjusting unit
39. Specifically, an amount of heat supplied per unit time to the
woody biomass B is adjusted when a degree of opening of the heating
gas amount adjusting damper 22 of the heating gas amount adjusting
device 7 is adjusted, and backup control is performed so that a
degree of opening of the heating gas amount adjusting damper 22 is
maintained in a predetermined range by adjusting a number of
rotations of the induced draft fan 23.
[0065] In addition, an amount of heat supplied per unit time to the
woody biomass B is adjusted when the rotational speed adjusting
unit 39 controls the drive device 14 and a number of rotations
(rotational speed) of the inner cylinder 9 is changed. For example,
when the number of rotations of the inner cylinder 9 is reduced, it
is possible to supply a larger amount of heat to the woody biomass
B.
[0066] As described above, in the carbide producing method of the
present embodiment, an amount of heat supplied per unit time to the
woody biomass B is controlled on the basis of the LHV of the
carbide C.
[0067] The LHV calculating process is a process of calculating an
LHV of the produced carbide C.
[0068] In the LHV calculating process, first, the carbide C
discharged through the chute 4 is introduced into one of the
storage tanks 26 (here, the first storage tank 26a). When a volume
of the carbide C stored in the first storage tank 26a reaches a
predetermined volume, the level meter 34 sends a signal to the
control device 6.
[0069] When the signal from the level meter 34 is received, the
control device 6 acquires a weight of the carbide C at that time
from the gravimeter 35. The control device 6 calculates a bulk
density of the carbide C by dividing the weight of the carbide C by
the volume. That is, when the volume of the carbide C is set as V,
and the weight of the carbide C at the volume V is set as M, the
bulk density D of the carbide C can be calculated by D=MN/V. In
addition, the bulk density of the carbide C can be measured
according to the JIS K 2151 6 "bulk density test method."
[0070] When calculation of the bulk density of the carbide C stored
in the first storage tank 26a is completed, the carbide C in the
first storage tank 26a is discharged according to a predetermined
method.
[0071] The control device 6 operates the switching damper 32 so
that the carbide C is introduced into the other storage tank 26
(the second storage tank 26b) at the same time as calculation of
the bulk density of the carbide C in the first storage tank 26a is
completed. Accordingly, the carbide C is stored in the second
storage tank 26b. An LHV of the carbide C is calculated by the same
method used to calculate the LHV of the carbide C in the first
storage tank 26a below.
[0072] When the first storage tank 26a and the second storage tank
26b are alternately used, it is possible to calculate the bulk
density of the carbide C continuously.
[0073] The LHV calculating unit 37 calculates an LHV of the carbide
C stored in the storage tank 26 using the table T (the correlation
shown in the graph in FIG. 3) in which a correlation between the
LHV of the carbide C and the bulk density of the carbide C is
stored.
[0074] The supplied heat amount control unit 38 controls at least
one of the heating gas amount adjusting unit 40 and the rotational
speed adjusting unit 39 on the basis of the LHV of the carbide C
calculated by the LHV calculating unit 37.
[0075] The supplied heat amount control unit 38 issues an
instruction to reduce the LHV of the carbide C when the LHV of the
carbide C is larger than X (refer to FIG. 2), that is, when the
crushability of the carbide C is favorable. For example, the
heating gas amount adjusting unit 40 is controlled such that an
amount of heating gas is reduced. When the LHV of the carbide C is
not sufficiently reduced due to the reduced amount of heating gas,
the rotational speed adjusting unit 39 is controlled, a rotational
speed of the inner cylinder 9 increases, and thus an amount of heat
supplied per unit time to the woody biomass B is reduced.
[0076] The supplied heat amount control unit 38 issues an
instruction to increase the LHV of the carbide C when the LHV of
the carbide C is smaller than X, that is, when the crushability of
the carbide C is poor. For example, the heating gas amount
adjusting unit 40 is controlled such that an amount of heating gas
is increased. When the LHV of the carbide C does not sufficiently
increase due to the increased heating gas, the rotational speed
adjusting unit 39 is controlled such that a rotational speed of the
inner cylinder 9 is reduced and an amount of heat supplied per unit
time to the woody biomass B is increased.
[0077] In addition, the control device 6 has a function of
correcting an amount of heat supplied per unit time to the woody
biomass B on the basis of a moisture content of the woody biomass B
measured by the non-contact thermometer 25 functioning as a
moisture content measuring device.
[0078] That is, when a moisture content of the woody biomass B
varies over a short time (for example, 50% to 55%), since an amount
of heat required for evaporation of moisture significantly
increases, an indicated value of the non-contact thermometer 25 is
reduced. When a trend (a decrease or an increase) of the
non-contact thermometer 25 is transmitted in advance to the LHV
calculating unit 37, before the LHV of the carbide C becomes
smaller than X, at least one of the heating gas amount adjusting
unit 40 and the rotational speed adjusting unit 39 is
controlled.
[0079] According to the above embodiment, when an amount of heat
supplied per unit time to the woody biomass B is controlled on the
basis of the LHV of the carbide C, it is possible to produce the
carbide C having favorable crushability. That is, when an amount of
heat supplied to the woody biomass B is adjusted using a
correlation between the LHV of the carbide C and the crushability
of the carbide C so that the LHV of the carbide C has an
appropriate value, it is possible to produce the carbide C with a
stable quality.
[0080] In addition, when the LHV of the carbide C is calculated
using a correlation between the bulk density of the carbide C and
the LHV of the carbide C, it is possible to ascertain the LHV of
the carbide C quickly. Since there is a high correlation between
the LHV of the carbide C and the bulk density of the carbide C, it
is possible to calculate the LHV of the carbide C immediately in
contrast to a method of analyzing the carbide C or the like.
[0081] In addition, when an amount of heat supplied per unit time
to the woody biomass B is corrected on the basis of the moisture
content of the pyrolyzed woody biomass B, if the moisture content
of the woody biomass B deviates from an appropriate numerical
value, the moisture content of the woody biomass B can be brought
close to an appropriate numerical value.
[0082] Here, while the two storage tanks 26 have been used as the
bulk density measuring device 5 in the above embodiment, the
present invention is not limited thereto. For example, when the
stored carbide C can be quickly discharged, the bulk density may be
measured using only one storage tank 26. In addition, three or more
storage tanks 26 may be installed.
[0083] In addition, while the LHV of the carbide C has been
estimated and calculated using the bulk density of the carbide C in
the above embodiment, the present invention is not limited thereto.
For example, the when LHV can be measured using a calorimeter, this
may be used.
REFERENCE SIGNS LIST
[0084] 1 Carbide producing device [0085] 2 Screw conveyor [0086] 3
External heat type pyrolysis gasification furnace [0087] 4 Chute
[0088] 5 Bulk density measuring device [0089] 6 Control device
[0090] 7 Heating gas amount adjusting device [0091] 8 Outer
cylinder [0092] 9 Inner cylinder [0093] 10 Movable side support
portion [0094] 11 Annular frame [0095] 12 Support member [0096] 13
Fixed side support portion [0097] 14 Drive device [0098] 15 Gear
[0099] 16 Drive motor [0100] 17 Pinion gear [0101] 18 Installation
surface [0102] 19 Heating gas combustion furnace [0103] 20 Heating
gas supply pipe [0104] 21 Heating gas delivery pipe [0105] 22
Heating gas amount adjusting damper [0106] 23 Induced draft fan
[0107] 24 Inspection window [0108] 25 Non-contact thermometer
(moisture content measuring device) [0109] 26 Storage tank [0110]
26a First storage tank [0111] 26b Second storage tank [0112] 27
Expansion [0113] 28 Duct [0114] 29 Upstream side duct [0115] 30
Branching portion [0116] 31 Downstream side duct [0117] 32
Switching damper [0118] 34 Level meter [0119] 35 Gravimeter [0120]
37 LHV calculating unit [0121] 38 Supplied heat amount control unit
[0122] 39 Rotational speed adjusting unit [0123] 40 Heating gas
amount adjusting unit [0124] B Woody biomass [0125] C Carbide
[0126] G Pyrolysis gas [0127] T Table
* * * * *